It may be useful, in a variety of settings, to utilize both a traditional engine (e.g., an internal combustion engine) and an infinitely variable power source (e.g., an electric or hydrostatic motor, a variable chain drive, and so on) to provide useful power. For example, a portion of engine power may be diverted to drive a first infinitely variable machine (e.g., a first electric machine acting as a generator), which may in turn drive a second infinitely variable machine (e.g., a second electric machine acting as a motor using electrical power from the first electrical machine). In certain configurations, power from both types of sources (i.e., an engine and an infinitely variable power source) may be combined for final power delivery (e.g., to a vehicle axle) via an infinitely variable transmission (“IVT”) or continuously variable transmission (“CVT”). This may be referred to as “split-mode” or “split-path mode” operation because power transmission may be split between the mechanical path from the engine and the infinitely variable path. Split-mode operation may be attained in various known ways. For example, a planetary gear set may be utilized to sum rotational power from an engine and from an electric machine, with the summed power transmitted downstream within an associated powertrain. This may allow for delivery of power (e.g., to vehicle wheels) with an infinitely variable effective gear ratio. Various issues may arise, however, including limitations relating to the maximum practical speed of variable power sources.
The operation of other types of transmissions, as well as IVT or CVT transmissions, may introduce various other issues. For example, in certain configurations, transmission shifts (e.g., transitions between different gear ratios) may result in jolts to a vehicle, lags or other transient effects on available power (e.g., at the wheels of a vehicle or at an attached tool or implement), or other detrimental effects on system performance and user experience.